Traccar reverse geocoding service

ok, thanks anton

I use the Traccar-Geocoder (version 1.0.8) with Anton's 'whole world index' and it works great.
But, just as @Slawek, I started experimenting with building my own index to keep it a bit up-to-date and because my server only has 16GB of RAM, I selected a couple of countries (Benelux, Germany, France etc.). The index build takes about 8 hours and says it finished successfully.
But my own index does not return a country or country code (same as @Slawek):

My own index

 curl "http://own.tg.index:3000/reverse?lat=45.88402&lon=6.43608&key=secret" | jq . -
{
  "display_name": "Route du Col des Aravis, 74220 La Clusaz",
  "address": {
    "road": "Route du Col des Aravis",
    "city": "La Clusaz",
    "state": "Auvergne-Rhône-Alpes",
    "county": "Haute-Savoie",
    "postcode": "74220"
  }
}

'world index'

 curl "http://world.tg.index:3000/reverse?lat=45.88402&lon=6.43608&key=secret" | jq . -
{
  "display_name": "Route du Col des Aravis, 74220 La Clusaz, France",
  "address": {
    "road": "Route du Col des Aravis",
    "city": "La Clusaz",
    "state": "Auvergne-Rhône-Alpes",
    "county": "Haute-Savoie",
    "postcode": "74220",
    "country": "France",
    "country_code": "FR"
  }
}

(Same goes for all the other countries in my own index.)
Any idea why the country (codes) are missing in self built indexes? Or how to solve it?